Phylogenetic analysis supports the monophyly of the South American mayfly genus Brasilocaenis Puthz, 1975 (Insecta: Ephemeroptera: Caenidae)

Abstract

Brasilocaenis Puthz, 1975 is a South American genus of Caenidae (Ephemeroptera). Except for their very distinct male genitalia, the species of this genus are morphologically similar to South American species of Caenis. We analysed the phylogenetic relationships among Brasilocaenis and related genera using morphological characters of both nymphs and adults and cladistic methods. This first phylogenetic analysis of Brasilocaenis was based on a matrix of 20 species, including six species of Brasilocaenis and 14 species of different genera (Alloretochus, Caenis, Clypeocaenis and Tasmanocaenis), and 35 characters analysed under implied weights (k ¼ 3). The analysis supports the monophyly of Brasilocaenis with a single synapomorphy d forceps fused with the styliger plate. South American Caenis form a paraphyletic group, with Brasilocaenis nested among them. Biogeographical analysis (spatial analysis of vicariance) based on distributional records for each species revealed seven vicariant events, the most important of which are: (i) a north-south separation coincident with a split between the Amazon and Atlantic forests, and (ii) two west-east separations in tropical South America indicating different historical events. We additionally describe Brasilocaenis atawallpa sp. n. from male imagos from Colombia, and suggest an amended diagnosis to include Brasilocaenis amacayacu n. comb. and Brasilocaenis elidioi n. comb.